Speed-changing mechanism.



L. CHEVROLET.

SPEED CHANGING MEGHANISM.

APPLICATION FILED JUNI; 1s, 190B.

Patented Apr. 27, 1909.

2 SHEETS-SHEET l.

L. CHEVROLET.

SPEED CHANGING MEGHANISM.

APPLICATION FILED JUNE 18l 190B.

9 1 9, 5 38. Patented Apr. 27, 1909.

2 SHEETS-SHEET 2.

LOUIS CHEVROLET, OF PHILADELPHIA, PENNSYLVANIA.

SPEED-CHANGING MECHANISM.

To all whom 'it may concern:

Be it known that I, LOUIS CHEVROLET, a citizen of Switzerland, residing at 5721 Oommerce street, Philadelphia, Pennsylvania, have invented a new and useful Speed- Changing Mechanism, of which the following is a specification. y

` My invention relates to speed changing mechanisms and my object is to provi e a mechanism for this purpose .whichrwill enable me to transmit to the driven section of the shaft either the full rate of revolution of the driving shaft or any desired lesser-rate thereof, and which will enable me to obtain .line 3- -3, 'Ei 1.

a like gradation of rate of revolution upon the reverse.

In the majority of s eed' transmission mechanisms for automob' e use'there are, for example, three speeds-a low, an intermediate and a high speedeach speed being obtained by bringing its own set of gears into positive contact with the power shaft. But 1n these cases we pass from a state of rest to the low' speed, from the low to the intermediate and from the intermediate to the high s eed, and no gradations of speed between tliese fixed rates is obtainable;

My object is to rovide a means whereby a finer radation of) speed transmission may be obtalned upon both forward and reverse movements. This I accomplish by the means hereinbelow described and shown in the accompanying drawings, in which- Figurel is a lon itudinal section of the entire mechanism. Fig. 2 is a section on the line 2 2, Fig. 1. Fig. 3 is a section on the Fig. 4 is a detail view of thevreverse c section on the line 5.-5, Fig. 1.'

In Fig. 1 the power shaft is divided, for the purposes of description, into the sections 11, 12 and l. Section 11, the driving section, of

the shaft extends from the right-hand side of .the drawing, as coming from the engine or motor, to a point bisected by the section line 3 3. Section 12, a driven section of the shaft, extends from the point crossed by the section line 3 3 to thereverse mechanism. Section 13, the remaining driven section of the s haft, extends from the reverse mechanism onward tothe left-hand side of the drawinv where it connects, in the case of automobie use, With the differential.

Thel right-hand end, as shown in Fig. l, of

section lof the power shaft terminatesin the -head p2 to which is secured the annular plate Specification of Letters Patent.

Application filed June 18, 1908.

showing other utcli member, and Fig. 5 is a.l

Patented 'April 27, 1909.

serial No. 439,152.

3. To the annular plate 3 are secured a series of brackets 4, 5 which support the valves 6, cylinders 7 and connecting tubing 8 which form art of the speed changing mechanism. Tli been omitted from Fig. 1 for the purpose of parts, but it is shown clearly in Fig. 2. Section 11 of the power shaft is cranked as at 9, 9l to carry the piston rods 1() and trunk pistons 11 whiclrare mounted in the cylinders 7 above described.

By reference to Fig. 2 it will be seen that the cylinders 7 are connected by the tubing 8 which-forms a continuous inter-communie connecting tubing 8 has cation between said cylinders, each length of v tubing between cylinders being controlled by a valve 6; and by a comparison o f Figs. 1 and 2 it will be seen that the entire system of inter-communicating cylinders, tubing and valves is mounted u on and secured to the annular plate 3 by tiie brackets 4, 5 hereinabove described,

Section 11 of the power shaft is mounted in the bearings 12 and 13, the inner race of,

the bearing 12 being secured to the shaft and the outer race to the gear casing 14. In like manner the inner race of the bearing 13 is secured to the left-hand end of section 11 of the power shaft, while `the outer race is secured in the enlarged head 2 of section` 1Z of the power shaft..

AThe spirally geared drum 15; Fig. 1, is

splined upon section 1 of the pou-cr shaft and isA slidable thereon by means of the collar 16, which is integral with said drum, the clutch arm 17 and clutch rod 18. The drum 15 is furnished with the clutch ins 19, one of which is shown in section in 4ig. 1 and one in perspective. These clutch pins `are adapted to enter clutch seats in the enlarged head 2`of section 12 of the power shaft, and a seat for any one of said clutch pins is provided in the end of crank 9 of section 1l of thepower shaft, as shown in Fi pins, three 1n 1. The ends of these clutch number, are shown in Fig. 3.

The valves 6 in the tubing 8 are controlled, as shown in Fig. 1, by the valvestems 20 and ears 21, the latter meshing with the spiralIy geared drum 15. One of these valves, with its stern and gear, \is shown in detail in Fig. 1, and the three valve stems, gears and the drum into which the latter mesh are shown in Fig. 3. 4

I Will now describe the mode of o eration of that portion ofmthe mechanism t 1e component parts of which have been hereinabove set forth. By reference to Fig. 2 it will be seen that a continuous, inter-com-4 municating passageway -is formed by the tubing 8 v which connects the open heads of the cylinders 7. This continuous passageway 1sY filled with a suitable Huid, such as glycerin or a heavy cylinder oil, openings being provided forv this purpose on the cen- A,

ter of each cylinderhead, said 'openings being closed by the cap screws, 34. A suitable opening (not shown) being provided in the gear casmg 14, the annular platev is rotated until one of the screw cappedopenings '34 into the passageway is brought opposite the opening inthe gear casing, when the cap screw34 is removed, the passageway filled and the cap screw replaced. f In Fig. 2 the valves 6 controlling the tubing sections of said continuous passageway are shown fully opened. If, now, the crank shaft be revolved an alternatin trunk pistonsv takes p ace in their respective c linders, little or no resistance being oered t creto by the oil,whichfilows freely to and fro through the passage-way as impelled by the stroke of the pistons. Butas soon as the valves are partially closed, by semi-rotation in their valve seats, a proportionate obstruction is oered tothe free flow of the -oil which in turn resists the free stroke of the y pistons until, when the valves are comcylinders, pistons, and tubing thereon rotatvmgm this casecn bloc.

If the valves 6 are now` artially o ened, allowing an impeded circ ation of o in the passageway, the' full rate of revolution of section Y11 of the power shaft is no longer transmitted -\to section /12 thereof, smce-two movements instead of one are now taking place in the mechanism shown in Fig. 2, namely, a slow strokeof the trunk pistons in their cylinders combined y with a revolution of the `annular plate 3rwith the cylinders, tubing and valves thereon. The rate of revolutin of the annular plate 3 andv consequently of section l? of the power shaftvto which it is secured will/be Vsomewhat vi; Iless than that of section 11fof the power shaft, y m consequence of the slbw stroke of the trunk pistons 1 l which by their motion preventthe full rate of revolution of' section 11 of the power shaft from being transmitted to sec'- 4 tion 2 thereof 'as was the case when the valves 6 were completely closed, allowing no stroke Iin the pistons and causingv the annular plate rise and fall of the f with its mechanism to rotate as a solid mass,

as above described.

In view of the foregoing explanation itl will be apparent that the highest speed is obtained when the valves 6 are closed, and that in proportion as they are opened the freedom of circulation of oil in the passageway is increased, lessening the resistance to the stroke of the pistons and decreasing the rate of rotation of the annular plate 3. When the valves 6 are fully opened and the How of oil in the passageway is unrestricted, no resistancel is offered to the stroke of the pistons and consequently no rotatory impulse is imparted to the annular plate 3 nor to section 12 of the power shaft. `It is thus apparent that by either partially or wholly opening or closing the valves 6 I am enabled to maintain section 12 of the power shaft in a state of rest, to set it in revolution, andv to'increase the rate of revolution by' any desired gradation up to the speed of section 11 of the power shaft.- By reference to Fig. 2 it will be seen that each of the istons 11 is at a different point ofits stro e, the rise and fall being counterbalancing. Itv thus results that the total space for circulation of oil in the' intercommunicating passageway and in the cylinder heads is always the same, the freedom of circulation only being restricted by semi-rotation of the valves I will now describe the means whereby the valves 6 are actuated. The spirally geared drum 15 with its collar 16 is splined upon section 12 of the power shaft, as hereinbefore described, and is adapted to slide thereon through the agency of the clutch arm 17 and clutch rod 18. The drum 15 meshes with the gears 21 yon the valve stems 20. In the posi* tion of parts shown in Fig. 1 the valves 6 are closed. If now the drum 1 5 is retracted on the shaftth'is movement operates to semirotate the gears 21 and to proportionately open the valves .6. 15 or the pitchof the lgears thereon may readily be determined in practice with reference to the dimensions of the valves and pas- The length of the drum sageway, so vas to afford the requisite grada` Ation in openin or closing the valves.

i The object o the clutch pins 19 with which the drum 15 is'furnished is as follows: When the valves 6 are shut, the full rate of revolution of section 11 of the power shaft, i. e. the

high s eed, is transmitted to section 12 thereof, as ereinbefore described,`the istons being' rigid in their cylinders. Whl e it is entirely feasible to run on the hi h speed in this manner, I desire to avoid t e consequent strain u on the speed changing mechanism. When, therefore, the highspeed is requlred, the drum 15 is moved b the clutch mechanism into the position s own in Fig. 1. As the valves' close by this movement of the drum, the' clutch pins 19 pass through seats in the enlarged head 2 and one of said pins enters a seat in the end of crank 9. This position of parts affords a direct and positive power transmission from section 11 to section 12 of the power shaft, distinct from although cooperating with the power transmission through the annular plate 3.

Having set forth the means whereby the desired Variations in speed transmission are secured, I will now describe the means whereby a reverse revolution of section 13 of the ower shaft is obtained. In Fig. 1 the leftand end of section 12 of the power shaft is mounted in the bearing 22 in a suitable supi porting bracket 23 integral withthe gear casing 14, and is furnished with the bevel gear 24, keyed upon the end thereof. Section 13 of the power shaft is mounted in the ,i bearing 25 at the point where the shaft passes through the gearcase, and is furnished with the fingered clutch member 26 which is mounted-free on the shaft, and the bevel gear 1 27, which is keyed upon t-he end of the shaft. Between the bevel gears 24 and 27 are arranged the pinions- 28, the shafts 29 whereof areinounted in the annular bearing 30 and are furnished with thethrust collars 3].-

The fingers of the clutch member 26, which is shown in detail in Fig. 4, are slotted to engage the heads of the pinion shafts 29, allowing the latter to turn freely therein, and the -body of the clutch member 26 is doublefaced, being provided with clutch pins on each face, the pins on the left-hand face, as in Fig. 1, being adapted to enter seats formed on the interior of the gear case while the pins lon the right-hand face are adapted to enter seats in the bevel gear 27. 'lhe clutch member 26'is actuated by the clutch arm32 and clutch rod 33.

While the clutch member 26 is in the position shown in Fig. 1 no transmission of power can take place from section 12 to section 13 of the power shaft and consequently section 13 of the power shaft is at rest. For while the revolution of bevel gear 24 is actuating the pinions 28, the latter cannot actuate bevel gear 27 since the clutch member 26 being free on the shaft allows the )inions 28 to turn about the power s aft. To transmit gear 27, which causes sections 13 and 12 of the power shaft to revolve in the same direction and at the same rate of speed. y

' Inorder to effect a reverse revolution of section 13 of the power shaft the clutch meinber 26 is moved to the left and is locked in the'clutch seats formed on the interior of the ions 28 and since the latter are by this means i prevented from rotation around the power shaft, they positively transmit a reverse revolution to bevel gear 27, thus causing section'13 of the power shaft to revolve at the same rate of speed but in a direction of revolution the reverse of that of section 12 of the power shaft. I desire to direct attention to a further feature of my invention as an entirety, namely, it is 'equally operative in all respects whether section 11 or section 13 be taken as the driving section of the power shaft.

While I have shownand described my invention as primarily designed and employed for automobile use, I do not in any sense confine myself to such use as it is manifestly open to a far more general mechanical application.

What I claim asmy invention and desire to secure by Letters Patent is 1. A two-section shaft and means for varying the rate of revolution of the second section relatively to that of the first'; said means consisting of a frame secured toI said second section cylinders carried thereby havingV a valved inter-communieation, piston heads in said cylinders cranked to said first section, a gear splined upon said second section and gears engaged therewith ada ted to actuate said valves, and means 'or sliding the gear on said second section substantially as described.

2. A two-section shaft and means for varying the rate of revolution of the second section relatively to that of the first; said means consisting of a plate secured to one end of said second section, cylinders carried thereby having a valved inter-communication, .piston heads in said cylinders cranked to said first section, a spiral gear splined Aupon said second section and geais engaged therewith on the Valve-stems of said valves, and means forl sliding said spiral gear upon scribed. A

3l A two-section power shaft and .means for varying the rate of revolution of the second section relatively to that of the first, said means consisting of an annular plate secured vsaid second section, substantially asdeto one end of said second section cylinders having a valved interconimunication, trunkpistons in said cylinders cranked to said first section, a s )irally geared drum splined upon said secon( section and gears engaged therewith on the valve-stems of said valves, and means, com rising a clutch collar, arm and rod," for sli( ing said spirally geared drum upon said second section, substantially as described.

4. A power-shaft formed in -two sections 11 and 12, and means for varying the rate of y formed'upon the meeting end of section l12, 20.

revolution of section 12 relativ-ely` to that of l valved communication each with other,

section 11 said means consisting of an annular plate secured to one end of section 12, a plurality of cylindersfequidistantly spaced upon and secured to said annular plate and g having a valved inter-communication, .trunkpistons mounted in said cylinders and cranked to section 11, a spirally geared drum s lined upon section 12 and gears engaged tiicrewith on the valve-stems of said valves, and means, comprising a' clutch collar, arm and rod, for sliding said spirally geared drum upon section 12, substantially as described.

5. A power-shaft formed in two sections 11 and 12, means for Varying the rate of revolution of section 12 relatively to that of section 11; said means consisting of a head van annular plate secured to said head, cylinders secured to saidv plate and having -a trunk-pistons mounted in said cylinders and cranked to section 11, a spirally geared clutch Y s lined upon section 12 and gears. engaged t erewith actuating said valves, means, comprising a clutch collar, arm and rod, for

sliding said spirally geared clutch upon sec-. Ation 12, and

means for positively locking sections 11 and 12 of the power shaft said means consisting of clutch seats through the head on the endof section 12 and avclutch seat in the crank of section 11and clutch pins on said spirally geared 'clutch adapted to enter said clutch seats, substantially as described.

- LOUIS CHEVROLET.

Witnesses: A

WILLIAM PHILLIPS, Jr., H. B. SCHERMERHORN. 

